A compact laser head with high-frequency stability for Rb atomic clocks and optical instrumentation

We present a compact and frequency-stabilized laser head based on an extended-cavity diode laser. The laser head occupies a volume of 200 cm³ and includes frequency stabilization to Doppler-free saturated absorption resonances on the hyperfine components of the ⁸⁷Rb  <i>D</i>₂ lines at 780 nm, obtained from a simple and compact spectroscopic setup using a 2 cm³ vapor cell. The measured frequency stability is ⩽ 2×10−12 over integration times from 1 s to 1 day and shows the potential to reach ≤2×10⁻¹³ over 10²−10⁵ s. Compact laser sources with these performances are of great interest for applications in gas-cell atomic frequency standards, atomic magnetometers, interferometers and other instruments requiring stable and narrow-band optical sources.